The mission of the Minnesota Obesity Center is to find ways to prevent weight gain and secondarily the onset of obesity and complications of obesity. Obesity is clearly a major source of illness and death, and is the most common nutritional ailment in the U.S. Despite its prevalence, there is little known about effective measures to prevent obesity, and therefore its attendant complications. Further, it is well known that obese individuals can more easily lose weight than maintain the loss. It now seems clear that the emphasis should be prevention of initial weight gain, and failing that, prevention of regain after weight loss. With the mission of prevention defined, our vision establishes three goals: 1) find the underlying problems that lead to obesity, 2) identify behaviors that lead to obesity and find ways to help change those behaviors, and 3) determine public health and public policy measures that will reduce the frequency and severity of obesity. Our Center is primarily a research center, so we plan encouragement and support of studies directed at these aims. With respect to these goals, the role of our center is to: assist principal investigators in conducting relevant research by providing resources through the core system; stimulate new interest and new collaborations in research into obesity, eating disorders and energy metabolism; support new research efforts in these areas related to obesity; and support education in obesity and eating disorders in our academic and public communities. The Minnesota Obesity Center has a strong and diverse research base consisting of 31 active investigators with 43 funded projects in obesity, energy metabolism and eating disorders, generating over 10 million dollars per year in grant support for their investigations. We propose the establishment of five core facilities including: 1) Administration will provide vision, leadership, and oversight of other core activities, 2) Basic Mechanisms Core will provide molecular biologic support for studies of nutritional affects on gene expression in a variety of tissues and support the emerging interest in linking epidemiological investigations with sophisticated genotyping, 3) Clinical Populations/Assessment Core will provide access to a large population of obese subjects and to individuals with eating disorders, varying in age from young to old and including most minority groups, 4) Epidemiology and Intervention Core is to make high quality services for epidemiological and behavioral intervention studies available to ONRC participants, 5) Human Metabolic Core Laboratory will provide access to established state-of-the-art methods for studying energy metabolism and nutrient partitioning at the whole body level in humans. In addition, resources for pilot/feasibility projects and an educational program will be established.